Clinical implications of positron emission tomography-negative residual computed tomography masses after chemotherapy for diffuse large B-cell lymphoma

Response to primary treatment in diff use large B-cell lymphoma (DLBCL) is highly predictive of long-term outcome. We evaluated the value of computed tomography (CT) fi ndings relative to positron emission tomography (PET) fi ndings, after the completion of chemotherapy. We retrospectively reviewed records from 491 patients with DLBCL at M. D. Anderson in 2001-2007; 22 patients were excluded for uncertain pathology and 169 for having received consolidative radiation, leaving 300 patients for the present analysis (median age, 61 years; 53% men, 47% women; 27% stage I-II, 73% stage III-IV; 73% completed 6-8 cycles of doxorubicin-based therapy). Factorsassoc ated with outcome on univariate analysis were response according to PET/CT and CT ( p 0.0001 for overall survival [OS], disease-specifi c survival [DSS] and progression-free survival [PFS]); number of chemotherapy cycles received (p 0.0001 OS, p 0.0001 DSS, p 0.002 PFS); the combined presence of Ki-67 - 50%, PET SUV 13 and bulky ( - 5 cm) disease ( p 0.005 OS, p 0.001 DSS, p 0.001 PFS); and International Prognostic Index (IPI) score ( p 0.004 OS, p 0.005 DSS, p 0.004 PFS). On multivariate analysis, PET/CT-negative, CT residual mass (- 2 cm) signifi cantly infl uenced OS, DSS and PFS ( p 0.0001.The presence of a residual mass - 2 cm on CT, coupled with negative fi ndings on PET/CT, has prognostic value in DLBCL.